In the feeding of paper sheets into the trays of sorting machines or sheet receivers of the kinds used with office copiers, printers or the like, placement of the sheets in a neat stack or set within the trays depends upon appropriate control of the infeed speed of the sheets, whether the trays are more or less horizontal and the size of the sheets of paper.
Sorting machines for use with copiers or receivers useful as mailboxes with printers may have moving trays or fixed trays, as exemplified in many prior patents, including U.S. Pat. No. 5,253,860 issued Oct. 19, 1993 to Hirose, et al, U.S. Pat. No. 5,186,454 issued Feb. 16, 1993 to Kitahara, and U.S. Pat. No. 4,974,828 issued Dec. 4, 1990 to Matsuo, et al., all of which are examples of moving bin sorters, and U.S. Ser. No. 332,181, filed Oct. 31, 1994 and U.S. Pat. No. 5,346,205 issued Sep. 13, 1994.
Each of the prior U.S. patents referred to above are of the moving bin type, have some type of means for modifying the sheet infeed speed of sheets entering the trays to assist in the proper placement of successive sheets in sets in the trays.
U.S. Pat. No. 5,253,860 utilizes an interface with the host machine to provide paper size information from the host to vary the paper feed motor speed depending upon paper size.
U.S. Pat. No. 5,186,454 utilizes a signal indicator of upward or downward movement of the trays of a moving tray sorter to vary the speed of the sheet infeed motor depending upon the direction in which the trays are being moved.
U.S. Pat. No. 4,974,828 utilizes a sheet trailing edge detector to vary the speed of a sheet infeed motor so that the motor drives the sheet initially at one speed to prevent any bending of the sheet between the sorter infeed roll and the host output roll, then a second speed corresponding to the output feed speed, and finally, a third speed faster than the output speed to finally feed the sheets into the trays.
However, in a fixed bin sorter mailbox as disclosed in U.S. Ser. No. 332,181 or in U.S. Pat. No. 5,346,205 where the trays are not moved, nevertheless, sheet infeed into fixed bins is secured by a trailing edge detector which controls sorting operations.
In any case, an object of all of the above referenced prior art is to assemble sets of sheets in the trays in a neat stack or set and the sheet speed or flight into the tray is a factor. In the case of most sorters the sheet is caused to be moved in the infeed direction, along an incline and then settle or slip back against a rear wall of the tray for registration of an edge of the set sheets. Thus, the flight path and speed of sheet movement over the rear wall of the tray are factors which impact the sheet set formation which are addressed by the prior art, as described above.